The ability to view internal anatomy has lead to significant advances in surgical capability and diagnosis. In particular, the number of procedures that can be performed in a minimally-invasive manner has increased, while such procedures have, in general, improved patient outcomes and reduced recovery time.
To provide visibility, the distal end of an endoscope can be inserted into the patient through a small hole. Usually, the endoscope is an elongated device that includes a lens at the distal end, and an eyepiece or camera at the proximal end. In addition, a working channel can allow for the delivery of surgical instruments, the collection of samples, and/or implantation of medical devices. Regardless of the configuration, the distal end of the endoscope is fed into the patient to view a surgical procedure and/or to provide observation of patient anatomy for diagnosis. Usually, a light source illuminates an area adjacent to the distal end of the endoscope. In some situations, the light source can be part of the endoscope. For example, the endoscope can include an illumination channel for the passage of light and/or an illumination device. Alternatively, a separate light source can be applied.
While many advances have been made for viewing patient anatomy with an endoscope, improvements in image quality would be beneficial. For example, light reflecting back into the detector can cause reflection-illuminated artifacts. These artifacts can appear as dark or bright ring structures during endoscopic visualization and obscure a portion of the viewing field. Accordingly, improvements to optical devices, such as endoscopes, and particularly improvements to image quality, could facilitate minimally-invasive procedures.